Cadmium Yellow Detection and Quantification by Voltammetry of Immobilized Microparticles

Abstract

Cadmium pigments (cadmium sulfide and cadmium sulfoselenide) produce intense colorings such as yellow, orange and red, and are well-known pigments in artists colors, plastics, glasses, ceramics and enamels. This makes cadmium yellow a widespread pigment and hence is very interesting to develop a simple and fast procedure for its identification. Here we propose a straightforward procedure that is harmless to the sample allowing its application to valuable samples and also to very small samples. Three different electrochemical procedures were developed for the identification and quantification of CdS. They are based on voltammetry of immobilized microparticles that suffer a reductive scan at 60 mVs À1 from þ 0.30 V to À 1.00 V producing peaks whose potential allows identification of the pigment. For quantitative purposes a pretreatment of À 1.50 V for 10 s was applied and then an oxidative scan was performed. The relative position of the Cd oxidation peak to the peak potential of an internal standard (AgCl) was used to proceed to the calibration.

Raman Vibrational Study of Pigments With Patrimonial Interest for the Chilean Cultural Heritage

“…The band at 987 cm -1 is characteristic to recognize the barium sulphate presence 18,19 . Spectrum of PIG028 matches the spectrum shown as Cadmium Yellow Lithopone published by K. Castro et al 20 ; the sample measured by them was also studied by electrochemistry detecting the presence of an important amount of ZnS (25.2%) 21 . Bands at 212 and 341 cm -1 may be ascribed to the longitudinal acoustic (LA) and to the (LO) phonon modes of ZnS crystal lattice, respectively 22 .…”

Solid‐State Electrochemical Reactions of Electroactive Microparticles and Nanoparticles in a Liquid Electrolyte Environment

“…Cepria and coworkers used the voltammetry of immobilized microparticles to detect and quantify the cadmium pigments (e.g., cadmium sulfide and cadmium sulfoselenide) used in artists paints, as well as in glasses, plastics, ceramics, and enamels [141]. For this, a simple, fast and reliable technique was developed that proved to be especially applicable for valuable art objects, as it was minimally invasive and required only nanogram quantities of material (see also Section 6.4.1).…”

The biochemical effects of occupational exposure to lead and cadmium on markers of oxidative stress and antioxidant enzymes activity in the blood of glazers in tile industry

“…In the ceramic tile industry, heavy metals such as lead (Pb) and cadmium (Cd) are employed as coloring powders to improve the strength of the products and polish them, as well as in the manufacture of various types of colored glaze (Cepriá et al, 2005). Glazers are heavily exposed to these toxic metals in glazing departments (Shouroki et al, 2015a, 2015b).…”